This project was initiated to study the role of catecholamines in the regulation of hypertension and stress, and was later extended to study the participation of other biogenic amines, estrogens and prostaglandins in the central regulation of neurovegetative functions. Catecholamines in postero-intermediate pituitary present a circadian rhythm and are regulated by estrogen receptors. In addition to catecholamines, serotonin and histamine participate in the central regulation of cardiovascular function. There are two distinct enzymes in the brain which are capable of synthesizing epinephrine. These enzymes are not connected anatomically. In addition to hypothalamic and brain stem catecholamines, septal catecholamines participate in the central stress response.